Convertible glenoid

ABSTRACT

A glenoid system (100) includes a baseplate (102) configured to attach to a glenoid cavity of a patient. In a primary configuration, a biocompatible plastic liner (332) can snap into a circumferential groove (120) on the baseplate, to attach to a lateral-facing surface (104) of the baseplate, at one or more locations around the groove. In a reverse configuration, a glenosphere (544, 644) can attach to an adapter (542, 642), which in turn can attach to the lateral-facing surface of the baseplate. The adapter can introduce lateral and/or angular offsets between the baseplate and the glenosphere, which can correct for unwanted offsets or inclinations. A middle peg extension (752) can screw onto a medial end of the middle peg (114), which can offer different combinations of peg length and peg material. The baseplates can be made available in various discrete sizes, each of which has the same distance between the middle peg and an inferior screw hole (112).

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/144,031, titled “Convertible Glenoid”, filed Apr. 7, 2015, theentirety of which is hereby incorporated by reference.

BACKGROUND

Shoulder arthroplasty is a surgical procedure in which all or part ofthe glenohumeral joint is replaced by one or more prosthetic implants.Frequently, shoulder arthroplasty is performed to relieve pain due tosevere arthritis or severe joint damage. There is ongoing effort toimprove the prosthetic components utilized in this surgical procedure.

OVERVIEW

In a natural glenohumeral (shoulder) joint, the glenoid cavity of thescapula (shoulder blade) is concavely curved. The head of the humerus(upper arm bone) is convexly curved, is held against the glenoid cavity,and can pivot in two dimensions around its center of curvature.

A prosthetic shoulder system can include elements that retain the sameconcavity of the natural joint. For instance, a prosthetic shouldersystem can include a glenoid component attachable to the scapula andhaving a concave surface, and a humeral component attachable to thehumerus and having a convex surface. Such a configuration is known as aprimary configuration.

Alternatively, the prosthetic shoulder system can include implantcomponents that have the opposite concavity of the natural joint. Forinstance, the glenoid component can include a convex surface, attachableto the scapula, and the humeral component can include a concave surface,attachable to the humerus. Such a configuration is known as a reverseconfiguration. The reverse configuration can benefit patients withdamaged rotator cuffs or other muscle deterioration.

A glenoid component that can accommodate both the primary configurationand the reverse configuration is known as a convertible glenoid. In someexamples, convertible glenoids can provide more flexibility for apractitioner during surgery than glenoids dedicated to primary orreverse configurations. In some cases, a convertible glenoid can reducea number of inventory parts needed to perform a shoulder surgery.

Any or all of the features described in this Overview can be usedindependently, or used together in any suitable combination. ThisOverview is intended to provide examples of the present patent document.It is not intended to provide an exclusive or exhaustive explanation ofthe invention. The Detailed Description below is included to providefurther information about the present convertible glenoid.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsdescribe similar components in different views. The drawings illustrategenerally, by way of example, but not by way of limitation, variousembodiments discussed in the present patent document.

FIGS. 1A-B show two views of an example of a glenoid system, inaccordance with some embodiments.

FIG. 2 shows a cross-section of the baseplate and middle peg from FIGS.1A-B, in accordance with some embodiments.

FIGS. 3A-B show two views of an example of a liner, in accordance withsome embodiments.

FIG. 4 shows a cross-section of the liner of FIG. 3, attached to thebaseplate of FIGS. 1A-B.

FIG. 5 shows a side view of an example of an adapter which can attach aglenosphere or glenoid shield to a baseplate, in accordance with someembodiments.

FIG. 6 shows a side view of another example of an adapter which canattach a glenosphere or glenoid shield to a baseplate, in accordancewith some embodiments.

FIG. 7 shows a side view of an example of a baseplate coupled to amiddle peg, where the middle peg is configured to attach to a middle pegextension, in accordance with some embodiments.

FIG. 8 shows a side view of an example of a plurality of baseplates, inaccordance with some embodiments.

FIG. 9 shows a side view of an example of a glenoid system in theprimary configuration, in accordance with some embodiments.

FIG. 10 shows a side view of an example of a glenoid system in thereverse configuration, in accordance with some embodiments.

FIG. 11 shows a side view of an example of a glenoid system in a mobilebearing configuration, in accordance with some embodiments.

FIG. 12 is a flow chart of an example of a method for implanting aglenoid system, in accordance with some embodiments.

DETAILED DESCRIPTION

In the following Detailed Description, the terms lateral, medial,superior, and inferior are used to describe the relative orientations ofparticular elements and features. It will be understood that these termsare used merely for convenience, and describe the relative orientationswhen the glenoid system is surgically implanted in a shoulder of apatient. For instance, a surface may be described herein as alateral-facing surface, because such a surface may face a lateraldirection when the glenoid system is implanted. One of ordinary skill inthe art will readily appreciate that the term lateral-facing surface canbe used to describe the orientation of such a surface, even when such asurface has not been surgically implanted. As such, the terms lateral,medial, superior, and inferior can all be considered to be precisemodifiers, which can describe elements or features that have not, or notyet, been surgically implanted.

A glenoid system can include a metallic baseplate configured to attachto a glenoid cavity of a patient. The baseplate can be configured tooperate in either a primary configuration (e.g., the same concavity ofthe natural shoulder) or a reverse configuration (e.g., the oppositeconcavity of the natural shoulder).

In the primary configuration, a biocompatibie plastic liner can snapinto a circumferential groove on the baseplate, to attach to alateral-facing surface of the baseplate, at one or more locations aroundthe groove. Attaching the plastic liner via snapping into thecircumferential groove on the baseplate can be more effective than otherattachment techniques, which can sometimes lead to disassociation of theplastic liner, overstuffing, or loosening of the implanted baseplate. Insome examples, using a plastic liner attached to a metal baseplate canbe more durable than using a purely plastic baseplate.

In the reverse configuration, a glenosphere or glenoid shield can attachvia taper fit to an adapter, which in turn can attach via taper fit tothe lateral-facing surface of the baseplate. The adapter can have alateral and/or angular offset between the taper elements, so that theadapter can controllably introduce lateral and/or angular offsetsbetween the baseplate and the glenosphere, or between the baseplate andthe glenoid shield. As such, the adapter can correct for unwantedoffsets or inclinations of the glenosphere or glenoid shield.

A middle peg can extend medially from the baseplate. An optional middlepeg extension can screw onto a medial end of the middle peg. The middlepeg extensions can be made available in different combinations of lengthand material. Using a system or kit of modular middle pegs can besmaller and less expensive than using a comparable system or kit ofglenoid baseplates that have integral middle pegs.

The baseplates can be made available in various discreteinferior-to-superior sizes, each of which has the same distance betweenthe middle peg and an interior screw hole. Using such a system or kitcan increase the spacing between the inferior and superior screws for aparticular anatomical size of the patient, which can increase stabilityof the baseplate during use. Using such a system or kit can also allowadditional elements to use a standardized spacing between the middle pegand inferior screw hole, regardless of anatomical size.

In some examples, the glenoid baseplate can define one or more cut-outsextending through the baseplate and shaped to accommodate an instrumentto relieve bone ongrowth or ingrowth. In some examples, the cut-outs canbe concentric with the middle peg. The cut-outs can be used for revisionsurgery, and need not be used during initial implantation.

The baseplate, circumferential groove, liner, adapter, glenosphere,middle peg, and middle peg extension are shown in FIGS. 1-11, and aredescribed in detail below.

FIGS. 1A-B show two views of an example of a glenoid system 100, inaccordance with some embodiments. Glenoid system 100 is but one exampleof a glenoid system; other suitable glenoid systems can also be used.

Glenoid system 100 can include a baseplate 102 that can attach to aglenoid cavity (e.g., on the lateral face of the scapula) of a patient.In some examples, baseplate 102 can be formed from a biocompatible metalor a biocompatible metal alloy, such as titanium or a cobalt-chromealloy. In some examples, one or more portions of the baseplate 102 thatcan contact bone can be treated to improve fixation to the bone.Examples of suitable fixation treatments can include surface blasting,hydroxyapatite coating (HAC), plasma spray, and others.

Baseplate 102 can define a lateral-facing surface 104. Lateral-facingsurface 104 can face laterally and can extend from a superior end 106 ofthe baseplate 102 to an inferior end 108 of the baseplate 102 when thebaseplate 102 is attached to the glenoid cavity. In some examples, thelateral-facing surface 104 can be concave. In other examples, thelateral-facing surface 104 can be convex.

Baseplate 102 can define a superior hole 110 through the lateral-facingsurface 104 proximate the superior end 106 of the baseplate 102.Baseplate 102 can define an inferior hole 112 through the lateral-facingsurface 104 proximate the inferior end 108 of the baseplate 102. Duringsurgery, a practitioner can screw the baseplate 102 to the glenoidcavity, with screws that extend through the superior hole 110 and theinferior hole 112 in the baseplate 102. In general, it is desirable toposition the superior hole 110 and the inferior hole 112 as far apart asis practical, which can stabilize the fixation of the baseplate 102 tothe glenoid cavity. In some examples, one or both of the superior hole110 and inferior hole 112 are countersunk, so that when the practitionerfully engages a screw through the respective hole, the head of the screwlies below (e.g., medial to) the lateral-facing surface 104. In someexamples, the screw can be poly-axial.

Baseplate 102 can be coupled to a middle peg 114 at a middle area 116between the superior hole 110 and the inferior hole 112. The middle peg114 can extend medially from the baseplate 102 when the baseplate 102 isattached to the glenoid cavity. Over time, bone can grow on and aroundthe middle peg 114, which can fixate the implanted baseplate 102. Insome examples, the middle peg 114 can be shaped to enhance fixation tothe bone. For instance, the middle peg 114 can have a generallycylindrical shape, with fins, dimples, depressions, or other featuresthat engage bone that grows around the middle peg 114. In some examples,one or more portions of the middle peg 114 can be treated to improvefixation to the bone. Examples of suitable fixation treatments caninclude surface blasting, hydroxyapatite coating (HAC), plasma spray,and others.

In some examples, baseplate 102 can define a circumferential edge 118around the lateral-facing surface 104. In some examples, thecircumferential edge 118 can have an elongated, oval, or pear-shapedfootprint, when viewed end-on from the medial or lateral direction. Inother examples, the circumferential edge 118 can have another suitablyshaped footprint.

In some examples, the circumferential edge 118 can define acircumferential groove 120 therein. The circumferential groove 120 canbe used to attach one or more additional elements to the baseplate 102.For instance, a biocompatible plastic liner can have one or more matingfeatures that snap into all or a portion of the circumferential groove120, thereby attaching the biocompatible plastic liner to the baseplate102. As another example, during surgery, the circumferential groove 120can support removable attachment of one or more trial components. Othersuitable components can also snap into the circumferential groove 120,as needed.

In some examples, baseplate 102 can further include one or more overhangelements 122. Overhang elements 122 can extend medially from respectivelocations along the circumference of the lateral-facing surface 104.Overhang elements 122 can form a lip with the circumferential groove120, so that once an element has snapped into the circumferential groove120, the overhang elements 122 block the element from being radiallyextended outward, out of the circumferential groove 120. In someexamples, overhang elements 122 are located at discrete locations aroundthe circumference of the lateral-facing surface 104, such as at fourequally-spaced locations around the circumference.

Baseplate 102 can optionally include one or more features that arebeneficial during revision surgery, e.g., surgery to remove an implantedbaseplate 102. For instance, baseplate 102 can include one or moreslots, holes, or apertures around the middle peg 114 that allow apractitioner to insert and/or circumferentially turn a tool around themiddle peg 114 to dissociate any bone growth from the middle peg 114.

In some examples, baseplate 102 can further define a first slot 124through the lateral-facing surface 104. First slot 124 can be elongatedcircumferentially around the middle area 116 and adjacent to the middlepeg 114. In some examples, first slot 124 can have an inner edgecoincident with a portion of an outer edge of the middle peg 114. Insome examples, first slot 124 can extend less than halfway around themiddle peg 114. In some examples, first slot 124 can be shaped and sizedto accommodate an instrument to relieve bone ongrowth or ingrowth on themiddle peg.

In some examples, baseplate 102 can further define a second slot 126through the lateral-facing surface 104. Second slot 126 can be elongatedcircumferentially around the middle area 116 and adjacent to the middlepeg 114. In some examples, second slot 126 can extend less than halfwayaround the middle peg 114. In some examples, second slot 126 can bediametrically opposed to first slot 124. In some examples, first slot124 and second slot 126 can be shaped and sized to accommodate aninstrument to relieve bone ongrowth or ingrowth on the middle peg 114.Slots 124, 126 are but one example of holes or apertures that canaccommodate a bone-dissociating tool. In some examples, baseplate 102can define more than two slots.

The circumferential groove 120, the overhang elements 122, the firstslot 124, and the second slot 126 can all be used singly on a baseplate102, all together on a baseplate 102, or in any combination with oneanother on a baseplate 102.

FIG. 2 shows a cross-section of the baseplate 102 and middle peg 114from FIGS. IA-B, in accordance with some embodiments. In FIG. 2, thesuperior direction is into the plane of the page, and the inferiordirection is out of the plane of the page. FIG. 2 shows portions of thelateral-facing surface 104, the circumferential groove 120, the firstslot 124 and the second slot 126. FIG. 2 also shows a portion of thesuperior hole 110, disposed behind the middle peg 114 in the view ofFIG. 2.

Additionally, FIG. 2 shows a recess 228 in the middle peg 114. In someexamples, the recess 228 can have a female taper 230. In some examples,the female taper 230 can be elongated in one direction, compared to aperpendicular direction. For instance, the female taper 230 can beelongated along the inferior-superior direction, compared to a directionperpendicular to the inferior-superior direction. In other examples, thefemale taper 230 can be rotationally symmetric. Recess 228 can serve twofunctions, related to additional elements described below.

First, for surgeries requiring the primary configuration, the recess 228can act as a guide for a centering feature on a biocompatible plasticliner attachable to the baseplate 102. In some examples, the centeringfeature can have an elongated cross-section that matches the elongationof the female taper 230. As the biocompatible plastic liner is broughtinto position, the elongations can ensure that the biocompatible plasticliner is azimuthally aligned with the baseplate 102. The recess 228 doesnot form a taper fit with the centering feature. The biocompatibleplastic liner and centering feature are shown in FIGS. 3A-B and 4, andare described in detail below.

Second, for surgeries requiring the reverse configuration, the recess228 can form a taper fit with an adapter, which in turn attaches to aglenosphere or a glenoid shield via another taper fit. The tapers on theadapter secure the adapter to the baseplate 102 and middle peg 114, andalso secure the adapter to the glenosphere or a glenoid shield. Thetapers on the adapter can be linearly and/or angularly offset withrespect to one another, so that the adapter can correct for at least oneof medio-lateral offset, supero-inferior offset, inclination, andretroversion between the baseplate 102 and the glenosphere or glenoidshield. The adapter is shown in FIGS. 5 and 6, and is described indetail below.

FIGS. 3A-B show two views of an example of a liner 332, in accordancewith some embodiments. Liner 332 can be formed from a biocompatibleplastic material, such as polyethylene, polyphenylsulfone (PPSU),polyoxymethylene (POM), and others. Liner 332 is but one example of abiocompatible plastic liner; other suitable liners can also be used.

In some examples, liner 332 can be shaped to snap into thecircumferential groove of the baseplate and thereby attach to thebaseplate. In some examples, when the liner 332 is attached to thebaseplate, the liner 332 can fully surround a lateral end of thebaseplate, including all or a portion of a circumferential edge of thebaseplate.

In some examples, liner 332 can include a flexible raised lip 334 aroundat least a portion of its circumference. The flexible raised lip 334 candeflect radially outward, engage the circumferential groove, and retractradially into the circumferential groove when the liner 332 is forcedagainst the baseplate.

In some examples, liner 332 can include a smooth face 336 facing thebaseplate, and a smooth face 338 facing away from the baseplate. Onceimplanted in a patient, smooth face 338 movably contacts a convexsurface on a corresponding element attached to the humerus, which formsthe artificial shoulder joint. The convex surface is typically metallic,so that the interface at smooth face 338 is between metal and plastic,and not between metal and metal.

In some examples, liner 332 can include a centering feature 340.Centering feature 340 can be made integrally with the liner 332, or madeseparately from the liner and attached to the liner 332. The centeringfeature 332 can extend medially through the baseplate, and extendmedially into recess 228 (FIG. 2) of the middle peg, when the liner 332is attached to the baseplate. As described above, the centering feature340 can have an elongated cross-section that matches the elongation ofthe female taper 230 (FIG. 2). As the liner 332 is brought intoposition, the elongations can ensure that the liner 332 is azimuthallyaligned with the baseplate. In some examples, the centering feature 340does not form a taper fit within the recess, and does not mechanicallysupport the liner 332.

FIG. 4 shows a cross-section of the liner 332 of FIG. 3, attached to thebaseplate 102 of FIGS. 1A-B. In the example of FIG. 4, the flexibleraised lip 334 on the liner 332 can engage the circumferential groove120 on the baseplate 102. In the example of FIG. 4, the centeringfeature 340 can enter into the recess 228 in the middle peg 114, whichis coupled to the baseplate 102. In the example of FIG. 4, the centeringfeature 340 can have minimal or no contact with the wall of the recess228. In some examples, in the event of a disassociation, this geometrycan allow a series of radiological spheres to be placed to supportidentification of the liner in the joint space.

The liners of FIGS. 3 and 4 can be used in the primary configurationsingly, or in any suitable combination with any or all of the otherfeatures discussed herein, such as the circumferential groove 120 (FIG.1), the overhang elements 122 (FIG. 1), the first slot 124 (FIG. 1), andthe second slot 126 (FIG. 1).

FIG. 5 shows a side view of an example of an adapter 542 which canattach a glenosphere 544 to a baseplate, in accordance with someembodiments. Adapter 542 can be formed from a biocompatible material,such as a titanium alloy, or other suitable biocompatible metal or abiocompatible metal alloy. FIG. 5 is but one example of an adapter 542;other suitable adapters can also be used.

Adapter 542 can have a first taper 546. The first taper 546 can be amale taper sized and shaped to form a taper tit with the recess, such asrecess 228 (FIG. 2) in the middle peg (FIGS. 1 and 2). The first taper546 can be centered around a first axis (A1).

Adapter 542 can have a second taper 548. The second taper 548 can besized and shaped to form a taper fit with a glenosphere or a glenoidshield. In the example of FIG. 5, the second taper 548 is a male taper,which is sized and shaped to form a taper fit with a female taper 550inside a recess 552 of the glenosphere 544. The second taper 548 can becentered around a second axis (A2).

In some examples, the second axis (A2) can be linearly offset from thefirst axis (A1). In some examples, the second axis (A2) can be angularlyoffset from the first axis (A1). In some examples, the second axis (A2)can be both linearly offset and angularly offset from the first axis(A1). Such an offset can correct for at least one of medic-lateraloffset, supero-inferior offset, inclination, and retroversion betweenthe baseplate and the glenosphere or glenoid shield.

FIG. 6 shows a side view of another example of an adapter 642 which canattach a glenosphere 644 to a baseplate, in accordance with someembodiments. Compared with the example of FIG. 5, the second taper 648and corresponding taper 650 on the glenosphere have reversed genders.FIG. 6 is but one example of an adapter 642; other suitable adapters canalso be used.

Adapter 642 can have a first taper 646, which can be a male taper sizedand shaped to form a taper fit with the recess in the middle peg. Thefirst taper 646 can be centered around a first axis (A1).

Adapter 642 can have a second taper 648. The second taper 648 can besized and shaped to form a taper fit with a glenosphere or a glenoidshield. In the example of FIG. 6, the second taper 648 is a femaletaper, which is sized and shaped to form a taper fit with a male taper650 on the glenosphere 644. The second taper 648 can be centered arounda second axis (A2). The second axis (A2) can be linearly and/orangularly offset from the first axis (A1).

The glenosphere 644 of FIG. 6 may be referred to as a monoblockglenosphere. Using the adapter 642 to connect the monoblock glenosphereto the baseplate has advantages over connecting the monoblockglenosphere directly to the baseplate, such as being able to correct forat least one of medio-lateral offset, supero-inferior offset,inclination, and retroversion between the baseplate and the glenosphereor glenoid shield.

The adapters of FIGS. 5 and 6 can be used in the reverse configurationsingly, or in any suitable combination with any or all of the otherfeatures discussed herein, such as the circumferential groove 120 (FIG.1), the overhang elements 122 (FIG. 1), the first slot 124 (FIG. 1), andthe second slot 126 (FIG. 1).

FIG. 7 shows a side view of an example of a baseplate 702 coupled to amiddle peg 714, where the middle peg 714 is configured to attach to amiddle peg extension 752, in accordance with some embodiments. Themiddle peg extension 752 can medially extend the middle peg 714.

In some examples, the middle peg extension 752 can be formed frombiocompatible metal or a biocompatible metal alloy, such as titanium ora cobalt-chrome alloy. In some examples, the middle peg extension 752can have a circular cross-section (e.g., the cross-section, taken in aplane perpendicular to the lateral-medial direction, can be rotationallysymmetric with respect to a lateral-medial axis). In some examples, themiddle peg extension 752 can have features that can encourage boneongrowth, such as fins, dimples, and the like. In some examples, one ormore portions of the middle peg extension 752 can be treated to improvefixation to the bone. Examples of suitable fixation treatments caninclude surface blasting, hydroxyapatite coating (HAC), plasma spray,and others. In some examples, Trabecular Metal can be used to enhancefixation.

In some examples, a lateral end of the middle peg extension 752 can havemale or female threads that mate with corresponding female or malethreads 754 at a medial end of the middle peg 714. In other examples, alateral end of the middle peg extension 752 can have a male or femaletaper that can form a taper fit with a corresponding female or maletaper at a medial end of the middle peg 714.

Extending the middle peg 714 with an attachable middle peg extension 752can allow greater flexibility in selecting a configuration for the areaof the extension that contacts bone. For instance, in some examples, themiddle peg extension 752 can be selected from a plurality of middle pegextensions. The plurality of middle peg extensions can be made availableas a kit, a system, or a collection of middle peg extensions. In someexamples, each middle peg extension in the plurality can have a uniquecombination of length and material. In some examples, a practitioner canselect a suitable length, from the discrete lengths available in theplurality of middle peg extensions, to best match an anatomy of thepatient.

A threaded or taper-fit middle peg extension, such as 752, can be usedsingly or in any suitable combination with any or all of the otherfeatures discussed herein, such as the circumferential groove 120 (FIG.1), the overhang elements 122 (FIG. 1), the first slot 124 (FIG. 1), thesecond slot 126 (FIG. 1), the centering feature 340 extending into therecess 228 of the middle peg 114 (FIG. 4), and the adapters 542, 642(FIGS. 5 and 6).

FIG. 8 shows a side view of an example of a plurality of baseplates802A-B, in accordance with some embodiments. Each baseplate 802A-B inthe plurality can have the same spacing (X) between the middle area818A-B and the inferior hole 812A-B. In some examples, the spacings aredenoted from a center of the inferior holes 812A-B to a center of themiddle peg 814A-B. Each baseplate 802A-B in the plurality can having aunique spacing (Y1, Y2) between the middle area 818A-B and the superiorhole 810A-B. In some examples, the spacings are denoted from a center ofthe superior holes 810A-B to the center of the middle peg 814A-B. Insome examples, the baseplates 802A-B in the plurality can be madeavailable as a kit, a system, or a collection of baseplates 802A-B.

A practitioner can select a baseplate 802A-B having aninferior-to-superior size matched to an anatomy of the patient. For agiven baseplate size, the inferior holes 812A-B and the superior holes810A-B can be spaced as far apart as is practical, which can increasestability of the baseplate 802A-B when the baseplate 802A-B is attachedto the glenoid cavity. In addition, the constant spacing between theinferior holes 812A-B and the middle area 818A-B can help ensure that aglenosphere is positioned consistently, regardless of a size of thebaseplate 802A-B.

The differently-sized baseplates shown in FIG. 8 can be used singly orin any suitable combination with any or all of the other featuresdiscussed herein, such as the circumferential groove 120 (FIG. 1), theoverhang elements 122 (FIG. 1), the first slot 124 (FIG. 1), the secondslot 126 (FIG. 1), the centering feature 340 extending into the recess228 of the middle peg 114 (FIG. 4), the adapters 542, 642 (FIGS. 5 and6), and the threaded or taper-fit middle peg extension 752 (FIG. 7).

FIG. 9 shows a side view of an example of a glenoid system 900 in theprimary configuration, in accordance with some embodiments. Glenoidsystem 900 can include a baseplate 902, a liner 932 configured to besnapped onto a lateral side of the baseplate 902, a middle peg 914extending medially from the baseplate 902, and an optional middle pegextension 952 configured to be screwed onto a medial end of the middlepeg 914. Liner 932 can be attached using the circumferential groove 120(FIG. 1), or with another suitable attachment mechanism.

FIG. 10 shows a side view of an example of a glenoid system 1000 in thereverse configuration, in accordance with some embodiments. Glenoidsystem 1000 can include a baseplate 1002, an adapter 1042 configured tobe attached to a lateral side of the baseplate 1002, a glenosphere 1044configured to be attached to a lateral side of the adapter 1042, amiddle peg 1014 extending medially from the baseplate 1002, and anoptional middle peg extension 1052 configured to be screwed onto amedial end of the middle peg 1014.

FIG. 11 shows a side view of an example of a glenoid system 1100 in amobile bearing configuration, in accordance with some embodiments. Themobile bearing configuration can have the same concavity of the reverseconfiguration (FIG. 10), but using a relatively shallow glenoid shield1156 instead of a glenosphere. Glenoid system 1100 can include abaseplate 1102, an adapter 1142 configured to be attached to a lateralside of the baseplate 1102, a glenoid shield. 1156 configured to beattached to a lateral side of the adapter 1142, a middle peg 1114extending medially from the baseplate 1102, and an optional middle pegextension 1152 configured to be screwed onto a medial end of the middlepeg 1114.

FIG. 12 shows an example of a flow chart of a method 1200 for implantinga glenoid system, such as 100 (FIG. 1), 900 (FIG. 9), 1000 (FIG. 10),1100 (FIG. 11). or others. The method can be executed by a practitioner,when planning for an operation and operating on a patient.

At operation 1202, the practitioner can select a configuration for theimplant. The configurations can include primary or reverse. Theselection can depend on the anatomy of the patient, and the reasons forperforming the shoulder replacement surgery.

At operation 1204, the practitioner can select a super-to-inferiorbaseplate size, from a plurality of discrete sizes, which most closelymatches an anatomy of the patient.

At operation 1206, the practitioner can select a length for the middlepeg, from a plurality of available peg lengths. The available peglengths can include a fixed length for a middle peg, plus a plurality ofdiscrete lengths for a middle peg extension.

At operation 1208, the practitioner can implant a baseplate, with theselected size, with the selected configuration, and with the selectedmiddle peg length.

The following non-limiting list of examples can further illustrate thepresent glenoid system.

In Example 1, a glenoid system can include a baseplate configured toattach to a glenoid cavity of a patient. The baseplate can define alateral-facing surface extending from a superior end of the baseplate toan inferior end of the baseplate. The lateral-facing surface can facelaterally when the baseplate is attached to the glenoid cavity. Thebaseplate can define a superior hole through the lateral-facing surfaceproximate the superior end of the baseplate. The baseplate can define aninferior hole through the lateral-facing surface proximate the inferiorend of the baseplate. The baseplate can define a circumferential edgearound at least a portion of the lateral-facing surface. Thecircumferential edge defining a circumferential groove therein.

In Example 2, the glenoid system of Example 1 can optionally furtherinclude a biocompatible plastic liner shaped to snap into thecircumferential groove of the baseplate and thereby attach to thebaseplate, the biocompatible plastic liner at least partially coveringthe lateral-facing surface of the baseplate when attached to thebaseplate.

In Example 3, the glenoid system of Example 2 can optionally furtherinclude wherein the biocompatible plastic liner includes a flexibleraised lip around at least a portion of its circumference, the flexibleraised lip being configured to deflect radially outward, engage thecircumferential groove, and retract radially into the circumferentialgroove when the biocompatible plastic liner is forced against thebaseplate.

In Example 4, the glenoid system of any one of Examples 2-3 canoptionally further include wherein the biocompatible plastic linerincludes a first smooth face configured to be oriented toward thebaseplate and a second smooth face configured to be oriented away fromthe baseplate.

In Example 5, the glenoid system of any one of Examples 2-4 canoptionally further include wherein the biocompatible plastic linerincludes a centering feature, the centering feature extending throughthe baseplate when the biocompatible plastic liner is attached to thebaseplate.

In Example 6, the glenoid system of any one of Examples 1-5 canoptionally further include wherein the baseplate is coupled to a middlepeg at a middle area between the inferior and superior holes, the middlepeg extending medially from the baseplate when the baseplate is attachedto the glenoid cavity.

In Example 7, the glenoid system of Example 6 can optionally furtherinclude wherein the centering feature is configured to extend into arecess in the middle peg, the centering feature forming a non-tapertaper fit with the recess in the middle peg.

In Example 8, the glenoid system of any one of Examples 6-7 canoptionally further include wherein the middle peg includes a threadedsurface configured to mate with a corresponding threaded surface on amiddle peg extension.

In Example 9, the glenoid system of any one of Examples 6-7 canoptionally further include wherein the middle peg includes a taperconfigured to form a taper fit with a corresponding taper on a middlepeg extension.

In Example 10, the glenoid system of any one of Examples 5-9 canoptionally further include wherein the centering feature has anelongated cross-section.

In Example 11, the glenoid system of any one of Examples 1-10 canoptionally further include wherein the baseplate is formed from abiocompatible metal or a biocompatible metal alloy.

In Example 12, the glenoid system of any one of Examples 1-11 canoptionally further include wherein the lateral-facing surface isconcave,

In Example 13, the glenoid system of any one of Examples 1-5 or 11-12can optionally further include wherein the baseplate is coupled to amiddle peg at a middle area between the inferior and superior holes, themiddle peg extending medially from the baseplate when the baseplate isattached to the glenoid cavity; and further comprising: an adapterhaving a first taper, the first taper being a male taper sized andshaped to form a taper fit with a recess in the middle peg, the adapterfurther having a second taper offset from the first taper, and thesecond taper being size and shaped to form a taper fit with aglenosphere or a glenoid shield.

In Example 14, the glenoid system of any one of Examples 1-5 or 11-12can optionally further include wherein the baseplate is coupled to amiddle peg at a middle area between the inferior and superior holes, themiddle peg extending medially from the baseplate when the baseplate isattached to the glenoid cavity, the baseplate defining a first slotthrough the lateral-facing surface, and the first slot being elongatedcircumferentially around the middle area and adjacent to the middle peg.

In Example 15, the glenoid system of any one of Examples 1-5 or 11-12can optionally further include wherein the baseplate is coupled to amiddle peg at a middle area between the inferior and superior holes, themiddle peg extending medially from the baseplate when the baseplate isattached to the glenoid cavity, and the middle peg configured to attachto a middle peg extension.

In Example 16, a glenoid system can include a baseplate configured toattach to a glenoid cavity of a patient, the baseplate defining alateral-facing surface extending from a superior end of the baseplate toan inferior end of the baseplate, the lateral-facing surface facinglaterally when the baseplate is attached to the glenoid cavity, thebaseplate defining a superior hole through the lateral-facing surfaceproximate the superior end of the baseplate, the baseplate defining aninferior hole through the lateral-facing surface proximate the inferiorend of the baseplate, the baseplate defining a circumferential edgearound at least a portion of the lateral-facing surface, and thecircumferential edge defining a circumferential groove therein; and abiocompatible plastic liner shaped to snap into the circumferentialgroove of the baseplate and thereby attach to the baseplate, thebiocompatible plastic liner at least partially covering thelateral-facing surface of the baseplate when attached to the baseplate,the biocompatible plastic liner including a flexible raised lip aroundat least a portion of a circumference of the biocompatible plasticliner, the flexible raised lip being configured to deflect radiallyoutward, engage the circumferential groove, and retract radially intothe circumferential groove when the biocompatible plastic liner isforced against the baseplate, the biocompatible plastic liner includinga centering feature, and the centering feature extending through thebaseplate when the biocompatible plastic liner is attached to thebaseplate.

In Example 17, the glenoid system of Example 16 can optionally furtherinclude wherein the baseplate is coupled to a middle peg at a middlearea between the inferior and superior holes, the middle peg extendingmedially from the baseplate when the baseplate is attached to theglenoid cavity.

In Example 18, the glenoid system of any one of Examples 16-17 canoptionally further include wherein the centering feature is configuredto extend into a recess in the middle peg, the centering feature forminga non-taper taper fit with the recess in the middle peg.

In Example 19, a glenoid system can include: a baseplate configured toattach to a glenoid cavity of a patient, the baseplate defining alateral-facing surface extending from a superior end of the baseplate toan inferior end of the baseplate, the lateral-facing surface facinglaterally when the baseplate is attached to the glenoid cavity, thebaseplate defining a superior hole through the lateral-facing surfaceproximate the superior end of the baseplate, the baseplate defining aninferior hole through the lateral-facing surface proximate the inferiorend of the baseplate, the baseplate defining a circumferential edgearound at least a portion of the lateral-facing surface, and thecircumferential edge defining a circumferential groove therein; and abiocompatible plastic liner shaped to snap into the circumferentialgroove of the baseplate and thereby attach to the baseplate, thebiocompatible plastic liner at least partially covering thelateral-facing surface of the baseplate when attached to the baseplate,the biocompatible plastic liner including a flexible raised lip aroundat least a portion of a circumference of the biocompatible plasticliner, the flexible raised lip being configured to deflect radiallyoutward, engage the circumferential groove, and retract radially intothe circumferential groove when the biocompatible plastic liner isforced against the baseplate, the biocompatible plastic liner includinga centering feature having an elongated cross-section, and the centeringfeature extending through the baseplate when the biocompatible plasticliner is attached to the baseplate.

In Example 20, the glenoid system of Example 19 can optionally furtherinclude wherein the lateral-facing surface is concave.

The above Detailed Description includes references to the accompanyingdrawings, which form a part of the Detailed Description. The drawingsshow, by way of illustration, specific embodiments in which theinvention can be practiced. These embodiments are also referred toherein as “examples.” Such examples can include elements in addition tothose shown or described. However, the inventors also contemplateexamples in which only those elements shown or described are provided.Moreover, the inventors also contemplate examples using any combinationor permutation of those elements shown or described (or one or moreaspects thereof), either with respect to a particular example (or one ormore aspects thereof), or with respect to other examples (or one or moreaspects thereof) shown or described herein. In this document, the terms“a” or “an” are used, as is common in patent documents, to include oneor more than one, independent of any other instances or usages of “atleast one” or “one or more.” In this document, the term “or” is used torefer to a nonexclusive or, such that “A or B” includes “A but not B,”“B but not A,” and “A and B,” unless otherwise indicated. In thisdocument, the terms “including” and “in which” are used as theplain-English equivalents of the respective terms “comprising” and“wherein.” Also, in the following claims, the terms “including” and“comprising” are open-ended, that is, a system, device, kit, article,composition, formulation, or process that includes elements in additionto those listed after such a term in a claim are still deemed to fallwithin the scope of that claim. Moreover, in the following claims, theterms “first,” “second,” and “third,” etc. are used merely as labels,and are not intended to impose numerical requirements on their objects.The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) can be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is provided to allowthe reader to quickly ascertain the nature of the technical disclosure.It is submitted with the understanding that it will not be used tointerpret or limit the scope or meaning of the claims. Also, in theabove Detailed Description, various features can be grouped together tostreamline the disclosure. This should not be interpreted as intendingthat an unclaimed disclosed feature is essential to any claim. Rather,inventive subject matter can lie in less than all features of aparticular disclosed embodiment. Thus, the following claims are herebyincorporated into the Detailed Description as examples or embodiments,with each claim standing on its own as a separate embodiment, and it iscontemplated that such embodiments can be combined with each other invarious combinations or permutations. The scope of the invention shouldbe determined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled.

The claimed invention is:
 1. A glenoid system, comprising: a baseplateconfigured to attach to a glenoid cavity of a patient, the baseplatedefining a lateral-facing surface extending from a superior end of thebaseplate to an inferior end of the baseplate, the lateral-facingsurface facing laterally when the baseplate is attached to the glenoidcavity, the baseplate defining a superior hole through thelateral-facing surface proximate the superior end of the baseplate, thebaseplate defining an inferior hole through the lateral-facing surfaceproximate the inferior end of the baseplate, and the baseplate beingcoupled to a middle peg at a middle area between the inferior andsuperior holes, the middle peg extending medially from the baseplatewhen the baseplate is attached to the glenoid cavity; and an adapterhaving a first taper, the first taper being a male taper sized andshaped to form a taper fit with a recess in the middle peg, the adapterfurther having a second taper offset from the first taper, and thesecond taper being size and shaped to form a taper fit with aglenosphere or a glenoid shield.